Ligament · Foot

Collateral ligaments of the metatarsophalangeal joints (foot)

The side ligaments of the joints at the ball of the foot, where each toe meets its long metatarsal bone. They are arranged exactly as the hand's knuckle ligaments are — obliquely, from a dimple on the side of the metatarsal head down to the base of the toe — but they are shorter and far less often asked to allow the toes to spread. The mechanics carry over from the hand: they are tightest when the toe is curled and slackest when it is bent upwards. That matters because upwards is precisely where the toes are at push-off, so at the moment these joints carry the most weight, their side ligaments contribute the least, and the pad underneath takes the load instead.